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Re: Search and Replace in 2D Array (Image) [message #66655 is a reply to message #66654] Thu, 28 May 2009 12:28 Go to previous message
David Fanning is currently offline  David Fanning
Messages: 11724
Registered: August 2001
Senior Member
vikramivatury@gmail.com writes:

> I have an image "m" which is [1229 x 1229] pixels that contains 1's
> and 0's. I also have an image "img" which is [1229 x 1229] that
> contains pixel IDs. For every 1 in image "m" it corresponds to a
> certain pixel ID in image "img". I am trying to write a loop in IDL
> that scans through the pixels of image "m" and when its get to a 1,
> spit out its information from "img". I used the 'where' function (w =
> where m gt 1.........ids = img(w)) and that worked fine in outputting
> a 1D array of 1510441 pixels, but I am trying to do it for a 2D array
> using loops.
>
> img = read_tiff('NP.tif')
> ids = fltarr(1229,1229)
>
> for i = 0,1228 do begin
> for j = 0,1228 do begin
> if (m(i,j) eq 1.) then begin
> ids(i,j) = img(m(i,j))
> endif
> endfor
> endfor
>
> Any suggestions would be great.

Well, don't do it like this. :-)

I suggest you investigate LABEL_REGION. *Much* faster!

Cheers,

David


--
David Fanning, Ph.D.
Coyote's Guide to IDL Programming (www.dfanning.com)
Sepore ma de ni thui. ("Perhaps thou speakest truth.")
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